In interlacing, the fields forming each frame are captured at two distinct time intervals. The pictures forming the video comprise a plurality of ordered lines. During one of the time intervals, video content for the even-numbered lines is captured, During the other time interval, video content for the odd-numbered lines is captured. The even-numbered lines may collectively be referred to as the top field, while the odd-numbered lines may collectively be referred to as the bottom field.
On an interlaced display the even-numbered lines are displayed on the even-numbered lines of the display during one time interval, while the odd-numbered lines are displayed on the odd-numbered lines of the display during another time interval.
With progressive displays, however, all of the lines of the display are displayed at one time interval. As noted above, the interlaced video pictures include even-numbered lines captured at one time interval, and odd-numbered lines captured at a second time interval. The deinterlacing process generates pictures for display during a single time interval from the interlaced video.
Deinterlacing by combining content from adjacent fields (known as weaving) is suitable for regions of the picture that are characterized by little or no object motion or lighting changes (known as inter-field motion). Displaying both the top field and bottom field at the same time interval can be problematic in cases where the video content has significant motion or lighting changes. Objects that are in motion are at one position when the top field is captured and another position when the bottom field is captured. If the top field and the bottom field are displayed together, a comb-like, or jagged edge affect will appear with the object. This is referred to as an artifact or as a weave artifact.
Alternatively, deinterlacers can generate a picture for progressive display by interpolating missing lines in a field from adjacent and surrounding lines. This is known as spatial interpolation, or “bobbing”. While spatial interpolation avoids artifacts in regions with high inter-field motion, spatial interpolation loses vertical detail and tends to result in a blurry picture.
Accordingly, deinterlacers commonly measure motion of the video content. In regions of a picture that are characterized by significant amounts of motion, spatial interpolation is chosen, while in regions of the picture that are characterized by little or no motion, weaving is chosen.
In some cases, high vertical detail may be mistaken for motion. Additionally, the presence of noise can also be mistaken for motion. In such cases, although a region of picture is characterized by little or no motion, spatial interpolation may be chosen and this may not be the optimum choice.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with embodiments of the present invention as set forth in the remainder of the present application with reference to the drawings.